1. Field of the Invention
The invention pertains to the art of air conditioning with induction units of the type in which a primary air flow induces a secondary air flow into a mixing chamber from which conditioned air is discharged to the space served.
2. Description of the Prior Art
Double induction systems for air conditioning are disclosed in U.S. Reissue Pat. Nos. 28,136 and 28,166. The basic arrangement as there disclosed includes a mixing box to which a primary air supply is introduced, with one dampered opening being in communication with the ceiling plenum in which the box is located and another dampered opening being in communication with the room. Typically, the air in the ceiling plenum will be at a higher temperature than that in the room due to the heating effect of the ceiling lighting. The primary air delivered to the box is at a relatively low temperature such as 45.degree. or 50.degree., and warmer air from the ceiling plenum and air from the room at room temperature may be introduced in varying proportions in accordance with positioning of the dampers for the two openings to the box. The dampers of course are arranged to work oppositely to each other so that when one damper is moving in an opening direction, the other damper is moving in a closing direction. The control of damper positioning is derived from changes in the room air temperature.
A disadvantage of the arrangement is that one or more damper motors and mechanical linkage arrangements are necessary for the prior art double induction system.
Accordingly, an aim of this invention is to avoid these disadvantages by providing a double induction mixing box devoid of dampers for controlling the proportioning of induced air from the two tempering air sources.
It is noted that control of air conditioning systems including an induction system with a fluidic arrangement is known as perhaps best exemplified by U.S. Pat. No. 3,799,246. However, the structural arrangement there shown and the device differ significantly in that the control is between one plenum in which a coil is located and another plenum which is simply a bypass.